tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * drivers/char/watchdog/ixp2000_wdt.c
3 *
4 * Watchdog driver for Intel IXP2000 network processors
5 *
6 * Adapted from the IXP4xx watchdog driver by Lennert Buytenhek.
7 * The original version carries these notices:
8 *
9 * Author: Deepak Saxena <dsaxena@plexity.net>
10 *
11 * Copyright 2004 (c) MontaVista, Software, Inc.
12 * Based on sa1100 driver, Copyright (C) 2000 Oleg Drokin <green@crimea.edu>
13 *
14 * This file is licensed under the terms of the GNU General Public
15 * License version 2. This program is licensed "as is" without any
16 * warranty of any kind, whether express or implied.
17 */
18
19#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
20
21#include <linux/module.h>
22#include <linux/moduleparam.h>
23#include <linux/types.h>
24#include <linux/timer.h>
25#include <linux/kernel.h>
26#include <linux/fs.h>
27#include <linux/miscdevice.h>
28#include <linux/watchdog.h>
29#include <linux/init.h>
30#include <linux/bitops.h>
31#include <linux/uaccess.h>
32#include <mach/hardware.h>
33
34static bool nowayout = WATCHDOG_NOWAYOUT;
35static unsigned int heartbeat = 60; /* (secs) Default is 1 minute */
36static unsigned long wdt_status;
37static DEFINE_SPINLOCK(wdt_lock);
38
39#define WDT_IN_USE 0
40#define WDT_OK_TO_CLOSE 1
41
42static unsigned long wdt_tick_rate;
43
44static void wdt_enable(void)
45{
46 spin_lock(&wdt_lock);
47 ixp2000_reg_write(IXP2000_RESET0, *(IXP2000_RESET0) | WDT_RESET_ENABLE);
48 ixp2000_reg_write(IXP2000_TWDE, WDT_ENABLE);
49 ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
50 ixp2000_reg_write(IXP2000_T4_CTL, TIMER_DIVIDER_256 | TIMER_ENABLE);
51 spin_unlock(&wdt_lock);
52}
53
54static void wdt_disable(void)
55{
56 spin_lock(&wdt_lock);
57 ixp2000_reg_write(IXP2000_T4_CTL, 0);
58 spin_unlock(&wdt_lock);
59}
60
61static void wdt_keepalive(void)
62{
63 spin_lock(&wdt_lock);
64 ixp2000_reg_write(IXP2000_T4_CLD, heartbeat * wdt_tick_rate);
65 spin_unlock(&wdt_lock);
66}
67
68static int ixp2000_wdt_open(struct inode *inode, struct file *file)
69{
70 if (test_and_set_bit(WDT_IN_USE, &wdt_status))
71 return -EBUSY;
72
73 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
74
75 wdt_enable();
76
77 return nonseekable_open(inode, file);
78}
79
80static ssize_t ixp2000_wdt_write(struct file *file, const char *data,
81 size_t len, loff_t *ppos)
82{
83 if (len) {
84 if (!nowayout) {
85 size_t i;
86
87 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
88
89 for (i = 0; i != len; i++) {
90 char c;
91
92 if (get_user(c, data + i))
93 return -EFAULT;
94 if (c == 'V')
95 set_bit(WDT_OK_TO_CLOSE, &wdt_status);
96 }
97 }
98 wdt_keepalive();
99 }
100
101 return len;
102}
103
104
105static const struct watchdog_info ident = {
106 .options = WDIOF_MAGICCLOSE | WDIOF_SETTIMEOUT |
107 WDIOF_KEEPALIVEPING,
108 .identity = "IXP2000 Watchdog",
109};
110
111static long ixp2000_wdt_ioctl(struct file *file, unsigned int cmd,
112 unsigned long arg)
113{
114 int ret = -ENOTTY;
115 int time;
116
117 switch (cmd) {
118 case WDIOC_GETSUPPORT:
119 ret = copy_to_user((struct watchdog_info *)arg, &ident,
120 sizeof(ident)) ? -EFAULT : 0;
121 break;
122
123 case WDIOC_GETSTATUS:
124 ret = put_user(0, (int *)arg);
125 break;
126
127 case WDIOC_GETBOOTSTATUS:
128 ret = put_user(0, (int *)arg);
129 break;
130
131 case WDIOC_KEEPALIVE:
132 wdt_enable();
133 ret = 0;
134 break;
135
136 case WDIOC_SETTIMEOUT:
137 ret = get_user(time, (int *)arg);
138 if (ret)
139 break;
140
141 if (time <= 0 || time > 60) {
142 ret = -EINVAL;
143 break;
144 }
145
146 heartbeat = time;
147 wdt_keepalive();
148 /* Fall through */
149
150 case WDIOC_GETTIMEOUT:
151 ret = put_user(heartbeat, (int *)arg);
152 break;
153 }
154
155 return ret;
156}
157
158static int ixp2000_wdt_release(struct inode *inode, struct file *file)
159{
160 if (test_bit(WDT_OK_TO_CLOSE, &wdt_status))
161 wdt_disable();
162 else
163 pr_crit("Device closed unexpectedly - timer will not stop\n");
164 clear_bit(WDT_IN_USE, &wdt_status);
165 clear_bit(WDT_OK_TO_CLOSE, &wdt_status);
166
167 return 0;
168}
169
170
171static const struct file_operations ixp2000_wdt_fops = {
172 .owner = THIS_MODULE,
173 .llseek = no_llseek,
174 .write = ixp2000_wdt_write,
175 .unlocked_ioctl = ixp2000_wdt_ioctl,
176 .open = ixp2000_wdt_open,
177 .release = ixp2000_wdt_release,
178};
179
180static struct miscdevice ixp2000_wdt_miscdev = {
181 .minor = WATCHDOG_MINOR,
182 .name = "watchdog",
183 .fops = &ixp2000_wdt_fops,
184};
185
186static int __init ixp2000_wdt_init(void)
187{
188 if ((*IXP2000_PRODUCT_ID & 0x001ffef0) == 0x00000000) {
189 pr_info("Unable to use IXP2000 watchdog due to IXP2800 erratum #25\n");
190 return -EIO;
191 }
192 wdt_tick_rate = (*IXP2000_T1_CLD * HZ) / 256;
193 return misc_register(&ixp2000_wdt_miscdev);
194}
195
196static void __exit ixp2000_wdt_exit(void)
197{
198 misc_deregister(&ixp2000_wdt_miscdev);
199}
200
201module_init(ixp2000_wdt_init);
202module_exit(ixp2000_wdt_exit);
203
204MODULE_AUTHOR("Deepak Saxena <dsaxena@plexity.net>");
205MODULE_DESCRIPTION("IXP2000 Network Processor Watchdog");
206
207module_param(heartbeat, int, 0);
208MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds (default 60s)");
209
210module_param(nowayout, bool, 0);
211MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started");
212
213MODULE_LICENSE("GPL");
214MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
215